1. Field of the Invention
The present invention relates to swimming goggles, and particularly to swimming goggles which have easily-adjustable buckles for tightening and loosening a head strap without taking off the swimming goggles.
2. Related Art
Generally, it is necessary to adjust a head strap when wearing swimming goggles. As is well known, the length of a head strap is being adjusted with buckles of frames of swimming goggles. Early buckles are only intended to allow the head strap to pass through. Once the head strap is to be adjusted, it has to be taken off from a wearer first, and then is manually moved backwards and forwards through the buckles in a direction of where it is passed through. Due to the inconvenient adjustment of the head strap, late buckles of swimming goggles are improved to have an engaging structure. The engaging structure has an engaging arm for being engaged with saw-shaped slots of a head strap so as to retain the head strap in place, whereby the head strap is only allowed to be tightened in one direction, without taking off the swimming goggles. To loosen the head strap, the engaging arm is to be disengaged with the saw-shaped slots. As a result, adjustment of the head strap of traditional swimming goggles depends entirely on the engagement and disengagement of the engaging arm and the saw-shaped slots.
Although the head strap of the above-mentioned traditional swimming goggles is adjustable without being taken off, the traditional buckles and head strap are still cumbersome and large in size, and therefore cause a higher cost of manufacturing.